The use of saccharides or sugars in liquid form, such as honey, is known to be effective as a dressing for wounds, burns and skin ulcers. Benefits include that inflammation, swelling and pain are quickly reduced, that sloughing of necrotic tissue occurs without the need for additional debridement, and that growth of tissues to repair the wound is stimulated. As a consequence, healing occurs rapidly with minimal scarring, and often without any necessity for skin grafting.
In addition to the use of saccharides in wound treatment, it is known that MMPs, which are part of the larger family of metalloproteinase enzymes, play an important part in wound healing. Although MMPs have the important role of breaking down proteins so that new tissue forms, when MMPs are present in a wound bed at too high a level, for too long a time, and in the wrong places, they begin to degrade proteins that are not their normal substrates. This can result in the unwanted destruction of beneficial proteins, such as growth factors, receptors and ECM proteins, that are essential for healing, and so ultimately impair healing. Substantial evidence has amassed that MMPs in general are highly elevated in wounds with delayed healing compared to acute healing wounds as discussed, for example, in Wounds International, “MMPs Made Easy” (Vol. 1, Issue 1, November 2009), which is incorporated herein by reference. The potentially damaging effects of these high levels is compounded by the fact that tissue inhibitors of metalloproteinases (“TIMPs”) levels in chronic wounds are generally slightly lower than in acute wounds.
Collagen dressings are used to suppress MMP levels, but scientific literature and opinion shows that such advanced dressings cannot be used until wounds are cleansed of necrotic tissue. The most preferred methods of cleansing of necrotic tissue are often surgery, curettage or sharp debridement. However, it may not always be possible to use one of these methods on patients who are not suitable candidates for such fast and immediate debridement. Collagenase enzyme, a MMP, is itself sometimes used to promote debridement, which, of course, cannot be mixed with a collagen dressing because the collagen dressing will engage the MMP, collagenase, which is being inserted into the wound for debridement.
Given that collagen promotes wound healing, it would be advantageous to the patient to be able to make use of and benefit from a collagen dressing during the weeks that are usually required for non-sharp debridement. Accordingly, it would be beneficial if some means were to be found provide non-sharp debridement while at the same time applying collagen to the wound.
U.S. Pat. No. RE 42,755 to Molan describes a wound dressing incorporating a honey composition that is at least 50% honey and mixed with a gelling agent to render it formable, pliable, flexible and moldable. Molan does not mention the MMP suppression effect of honey, nor does it suggest that the MMP suppression activity of honey may be synergistically augmented via the introduction of variable quantities of collagen.
U.S. Pat. No. 4,844,898 to Komori, U.S. Pat. No. 3,767,784 to Gluck, and U.S. Pat. No. 4,401,651 to Knutson also discuss saccharide compositions for use with wound dressings. Each of these references fails to recognize that the efficacy of saccharides is driven by the exertion of osmotic pressure. This osmotic pressure effect causes wound exudates to flood in from deep within tissue into the wound site, dissolving necrotic tissue and cleansing the wound. In addition, these patents were written prior to the introduction of the concept that MMPs are responsible for wound chronicity, and they do not mention collagen as a compositional additive to honey or any other saccharide.
Accordingly, a need exists for a composition that provides non-sharp debridement while also controlling the level of MMPs present in the wound.